Waterpebble is a unique tiny gadget that monitors the amount of water you consume during a shower and helps you save water. The tiny pebble shaped gizmo placed below your shower checks the water outflow via the plughole. Using your first shower as a benchmark, the waterpebble alerts you using different lights ranking your water usage. So once you have set the benchmark with your first shower, you can use the indicator lights by waterpebble to alert your self and reduce your water wastage. Video demo below.
Water pebble lasts for 4-6 months and does not allow you to change batteries. However, you can reset the pebble pretty easily.